The present invention generally relates to industrial robots and more particularly to a data conversion system used in an industrial robot system for feeding a control data to a plurality of robots in an off-line mode.
Conventionally, there is an industrial robot system including a number of robots. In such a robot system, there is a case that each of the robots in the system is required to perform an identical operation. In such a case, a human operator teaches a desired operation to a single robot provided independently from a production line. Such an independent robot is called mother robot. Responsive to the teaching, the mother robot produces a control data specifying its operation and this control data is obtained in a form of a recording medium such as a floppy disk on which the control data is recorded. In correspondence to the number of robots in the production line, a number of floppy disks recorded with the control data are obtained from the mother robot and these floppy disks are loaded on the respective robots in the actual production line called line robots. By doing so, each of the line robots performs the operation which is taught to the mother robot and the human operator can save the time to teach an identical operation to numerous robots in the system.
The control data specifies a rotational angle of an arm of the robot about a number of rotational axes provided in correspondence to articulations in the arm which specifies the degree of freedom of the robot. This number of rotational axes may be six, for example Thus, by controlling the rotation according to the control data, the movement of the arm which the human operator has taught to the mother robot is played back.
In the actual robot system, each robot in the production line usually shows a minute difference in the operation from that of the mother robot, mainly due to the manufacturing error of various part of the robot or due to the error at the time of assembly of the robot. Thus, the actual movement of the arm of the individual robot in the production line is slightly different from that of the arm of the mother robot. Further, the movement of the arm of the robot in the production line is different from one another even when an identical control data is used. Thus, in order to make the movement of the arm of the robot exactly identical to that of the mother robot for all of the robots in the production line, it is necessary to correct the control data for the individual robots in the production line.
Conventionally, such a correction of the control data was performed by the operator at the site of the individual robots when the floppy disk is loaded on a controller of the robot. However, such a correction, made individually for each of the plurality of robots in the production line, is tedious and wastes substantial time. Further, there is a problem in that the production line cannot be started up until the correction for all of the robots in the line is completed when a plurality of robots are used in a single production line. Furthermore, such a manual correction tends to invite error in the operation of the human operator.